用基因材料進行治療的技術。這種基因材料可以是基因，基因替代物或cDNA、RNA甚至小的基因片段。引入的遺傳材料可以在幾方面有治療作用：它可以合成一個蛋白質替代缺陷或遺失蛋白，或修正和修飾一項特定的細胞功能，或引發免疫反應。在基因治療方法中，基因材料可以以多種方式引入病人體內。它可以以基因疫苗的方式注射，或者將攜帶治療基因作為其原有基因的一部分的生物工程病毒引入體內。使用的病毒可以是腺病毒、AAV、反轉錄病毒、皰疹病毒。脂質體也可攜帶治療基因到細胞內。

The technology that uses genetic material for therapeutic purposes. This genetic material can be in the form of a gene, a representative of a gene or cDNA, RNA or even a small fragment of a gene. The introduced genetic material can be therapeutic in several ways: It can make a protein that is defective or missing in the patient’s cells (as would be the case for a genetic disorder), or one which will correct or modify a particular cellular function, or a protein that elicits an immune response. In gene therapy approaches, the genetic material may be introduced into the patient in several different ways. It can be directly injected for some applications in a process known as genetic vaccination, or it can be introduced by using bioengineered viruses that will carry the therapeutic gene as part of their own genetic cargo and deliver it into the cell. The viruses that are commonly used for this purpose are adenovirus, adeno-associated virus (AAV), retrovirus, lentivirus and herpes virus. Reagents known as liposomes can also carry therapeutic genes into cells.